CMES-Vol. 69, No. 1, 2010

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Self-Adaptive Differential Evolution Based on the Concept of Population Diversity Applied to Simultaneous Estimation of Anisotropic Scattering Phase Function, Albedo and Optical Thickness
F. S. Lobato¹, V. Steffen Jr², A. J. Silva Neto³
CMES-Computer Modeling in Engineering & Sciences, Vol.69, No.1, pp. 1-18, 2010, DOI:10.3970/cmes.2010.069.001
Abstract Differential Evolution Algorithm (DE) has shown to be a powerful evolutionary algorithm for global optimization in a variety of real world problems. DE differs from other evolutionary algorithms in the mutation and recombination phases. Unlike some other meta-heuristic techniques such as genetic algorithms and evolutionary strategies, where perturbation occurs in accordance with a random quantity, DE uses weighted differences between solution vectors to perturb the population. Although the efficiency of DE algorithm has been proven in the literature, studies indicate that the efficiency of the DE methods is sensitive to its control parameters (perturbation rate and crossover rate) and there… More >

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Calculation of Potential Second Derivatives by Means of a Regularized Indirect Algorithm in the Boundary Element Method
H.B. Chen¹, Masa. Tanaka²
CMES-Computer Modeling in Engineering & Sciences, Vol.69, No.1, pp. 19-42, 2010, DOI:10.3970/cmes.2010.069.019
Abstract Highly accurate calculation of derivative values to the field variable is a key issue in numerical analysis of engineering problems. The boundary integral equations (BIEs) of potential second derivatives are of third order singularities and obviously the direct calculation of these high order singular integrals is rather cumbersome. The idea of the present paper is to use an indirect algorithm which is based on the regularized BIE formulations of the potential second derivatives, following the work of the present first author and his coworkers. The regularized formulations, numerical strategies and example tests are given for both potential first and second… More >

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Numerical Solution of Dual Phase Lag Model of Bioheat Transfer Using the General Boundary Element Method
Ewa Majchrzak¹
CMES-Computer Modeling in Engineering & Sciences, Vol.69, No.1, pp. 43-60, 2010, DOI:10.3970/cmes.2010.069.043
Abstract Heat transfer processes proceeding in domain of heating tissue are discussed. The typical model of bioheat transfer bases, as a rule, on the well known Pennes equation, this means the heat diffusion equation with additional terms corresponding to the perfusion and metabolic heat sources. Here, the other approach basing on the dual-phase-lag equation (DPLE) is considered in which two time delays τ_q, τ_T (phase lags) appear. The DPL equation contains a second order time derivative and higher order mixed derivative in both time and space. This equation is supplemented by the adequate boundary and initial conditions. To solve the problem… More >

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Aerodynamic Shape Optimization of Airfoils in Unsteady Flow
Anant Diwakar¹, D. N.Srinath¹, Sanjay Mittal¹
CMES-Computer Modeling in Engineering & Sciences, Vol.69, No.1, pp. 61-90, 2010, DOI:10.3970/cmes.2010.069.061
Abstract Aerodynamic shape optimization of airfoils is carried out for two values of Reynolds numbers: 10³ and 10⁴, for an angle of attack of 5^o. The objective functions used are (a) maximization of lift (b) minimization of drag and (c) minimization of drag to lift ratio. The surface of the airfoil is parametrized by a 4^th order non-uniform rational B-Spline (NURBS) curve with 61 control points. Unlike the efforts in the past, the relatively large number of control points used in this study offer a rich design shape with the possibility of local bumps and valleys on the airfoil surface. The… More >

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